Enantiomeric Water-Soluble Octopus[3]arenes for Highly Enantioselective Recognition of Chiral Ammonium Salts in Water

Study of enantioselective recognition in water by synthetic chiral macrocyclic receptors is undoubtedly of theoretical and practical significance, but it is a big challenge to achieve the enantioselective recognition with both high enantioselectivity and high affinity in water probably due to the deficiency of such water-soluble macrocyclic receptors with stable chiral cavities. Herein, we report a new class of chiral macrocyclic arenes named octopus[3]arenes. The enantiomeric macrocycles are composed of three homochiral ethenoanthracene subunits, and they can be synthesized by two pathways and then easily converted into water-soluble octopus[3]arenes P-1 and M-1. Notably, P-1 and M-1 with the rigid hexagonal structures and stable chiral hydrophobic cavities exhibit highly enantioselective recognition towards three pairs of chiral ammonium salts in water with the association constant up to 10(6) M-1 and the SIR selectivity up to 12.89.

Automated summary

The study of enantioselective recognition in water by synthetic chiral macrocyclic receptors is important both theoretically and practically. However, achieving enantioselective recognition with high enantioselectivity and affinity in water has been a challenge due to the lack of stable water-soluble macrocyclic receptors with chiral cavities. In this study, a new class of chiral macrocyclic arenes called octopus[3]arenes was introduced. These macrocycles, composed of three homochiral ethenoanthracene subunits, can be easily converted into water-soluble octopus[3]arenes P-1 and M-1. P-1 and M-1 exhibited highly enantioselective recognition towards three pairs of chiral ammonium salts in water, with association constants up to 10(6) M-1 and SIR selectivity up to 12.89.